Anticardiolipin antibody (ACA)
Copyright 2014 by Mosby, Inc., an imprint of Elsevier Inc.
Pagana: Mosby’s Manual of Diagnostic and Laboratory Tests, 5th Edition
Systemic Lupus Erythematosus (SLE)
A 24-year-old woman had been complaining of multiple joint and muscular pains and
stiffness in the morning. She also noted some hair loss and increased skin sensitivity to light.
Her physical examination showed slight erythema around the cheekbones and some swelling
in the joints of her hands.
Routine laboratory work Within normal limits (WNL), except for mild
Urinalysis, p. 956 Profuse proteinuria and cellular casts
Antinuclear antibody (ANA), p. 88 1:256 (normal: <1:20)
Anti-DNA 398 units (normal: <70 units)
Anti-ENA Positive (normal: negative)
Anticardiolipin antibody (ACA), p. 68
Immunoglobulin (Ig) G 96 g/L (normal: <23 g/L)
IgM 78 mg/L (normal: <11 mg/L)
Erythrocyte sedimentation rate (ESR), p. 221 75 mm/hour (normal: ≤20 mm/hour)
Immunoglobulin electrophoresis, p. 312
IgG 1910 mg/dL (normal: 565-1765 mg/dL)
IgA 450 mg/dL (normal: 85-385 mg/dL)
IgM 475 mg/dL (normal: 55-375 mg/dL)
Total complement assay, p. 172 22 hemolytic units/mL (normal: 41-90
The positive ANA and ACA tests strongly supported the diagnosis of systemic lupus
erythematosus (SLE). The patient also had a facial rash suggestive of SLE. The elevated ESR
indicated a systemic inflammatory process. The immunoelectrophoresis results were
compatible with either RA or SLE; however, a decreased complement assay is commonly
associated with SLE. The abnormal urinalysis indicated that the kidneys also were involved
with the disease process. The patient was treated with steroids and did well for 7 years.
Unfortunately, her renal function deteriorated, and she required chronic renal dialysis.
Critical Thinking Questions
1. Explain the significance of the urinalysis results as they relate to renal involvement with SLE.
2. Why is the ESR increased in inflammatory conditions?